Wi-Fi on a Boat
Making shore-based Wi-Fi Internet work well on a boat. Common Problems In locations where shore-based Wi-Fi signals are strong, using them for Internet access on a boat is comparable to using Wi-Fi hotspots on land. However, the marine environment tends to exacerbate general Wi-Fi problems and create other problems of its own: * Boat hulls and sailboat masts can block radio signals, reducing range. * Movement of other boats can cause interruptions of Wi-Fi connections. * Location of a Wi-Fi antenna in a cabin below deck can further reduce range. * It may be difficult to get close enough to the Wi-Fi access point for sufficient signal, especially when anchored. * Boat movement can result in aiming problems with highly directional antennas (even when tied up). * Moisture in the marine environment can result in electronic failures. Improving Wi-Fi Range On the Internet you can find Wi-Fi systems suggesting that 3, 5, or even longer ranges are possible between your boat and a shore side Wi-Fi signal. Is this possible? It depends on the equipment being used on shore. Much over 5 miles is not realistic however, unless you own and control the equipment on shore as well. To get that type of range may require a very high gain parabolic or yagi antennas which focus the signal into a very narrow beam pointed directly at the other end of the link. A boat at anchor, on a mooring, or even tied to a dock is not stable enough to use such an antenna as any movement at all would drop the connection. On a boat we must use an omni-directional antenna that can send and receive signals in all directions as we swing at anchor or on our moorings. There are good high gain omni directional antennas (don't want higher than 9dBi on an boat however, see below). Getting longer ranges with an omni-directional antenna is certainly possible, however you are much more dependent on the equipment on shore to be of high power. The range of the connection and the quality of the connection depends entirely on the two way conversation between the equipment on your boat, and the equipment being used on shore. If better equipment is in use on both sides, ranges of 5 miles are certainly possible. However, this is not what is to be expected from a normal access point on shore. A mile range is a more realistic and common expectation of what you will see with good equipment on your boat and average equipment on shore. Even after establishing a long distance connection to shore, the quality of the connection will stll be influenced by many factors: other signal noise (other WiFi and telecommunications equipment) in the area, obstructions and obstacles between the access point ( i.e. in a basement vs the front porch) and your boat, and type of equipment on shore. Sometimes VOIP (Skype) will work for miles, and sometimes it won't work at less than 1/2 mile. Higher Power While it may seem that higher power Wi-Fi might help to improve your range, that's not necessarily true, since higher power only helps on transmit, not receive. Thus it's only likely to help if the other end of your connection is using higher power as well, which is often not the case. In other words, what you may well wind up with is an alligator, big mouth but small ears. Also, unnecessarily high transmit power will tend to increase your interference with other Wi-Fi users, making you a bad neighbor. It's usually much better to just improve your antenna, which helps both transmit and receive. Better Antenna Usually the best way to improve range is to use a better antenna (or reflector with a standard antenna), which helps both transmit and receive. Better antennas work by being directional: * concentrating radio energy/sensitivity to/from the desired direction instead of wasting it in pointless directions, and * reducing interference from other radio sources not in the desired direction (path). The improvement in antenna performance is referred to as gain, where a higher number indicates the amount of performance improvement expressed in dBi. It takes an increase of 6 dBi to double range; e.g., as compared to a typical 2 dBi antenna, an 8 dBi antenna has double the range. However, a highly directional antenna can be problematic on a boat, since it must be kept aimed accurately at the remote end of the connection, which can be difficult on a boat floating in the water (even when tied up). The width (angle) of the directional pattern (both vertically and horizontally) can be used to see how accurately the antenna must be aimed. The simplest and easiest improvement is to use a higher-gain omnidirectional antenna (4-8 dBi), thereby avoiding the need to aim the antenna horizontally (point it at the shore-based wireless access point). Such an antenna works by concentrating energy/sensitivity in the horizontal direction that would otherwise be wasted vertically (up and down). Beyond about 8 dBi the vertical beam angle becomes so narrow that vertical aiming can be problematic on a boat: |align="center"| |} | |} There is a fair amount of discussion here about beam width and why a boat must have an omni antenna with about 8 dBi or less gain. Let us do a practical test of this. Take your hand bearing compass out and site a location about 1000 feet from your boat. Then slowly turn six degrees and look at that point. Now imagine that distance turned vertically and that is the beam with of an omni antenna with a beam with of 6 degrees at 1000 feet. Repeat this for a point 2000 feet away, then 3000 feet away, then 6000 feet away. This test convinced me to experiment with high gain omni antennas from the practical perspective of a sailing boat. I am not disagreeing that at close proximity that a lower gain antenna is better. But as the distance increases the effective beam width increases. Years of actual experience aboard sailing boats confirms that higher dBi gain omni antennas work well on a boat at anchor as well as at a dock close to the shore side station. Antenna Location Higher antenna locations tend to have less interference from obstructions (e.g., biminis, dodgers, booms, and other very close proximity boats) than lower locations since there are more obstructions on a boat closer to deck level, so in general, it's a good idea to locate the antenna as high as is practical. WiFi is line of sight, and the use of a medium gain antenna (4dBi-9dBi) will provide a fair amount of flexibility in accessing WiFi access points on shore regardless of the height of the antenna on the boat due to it's wide cone of transmission. Use of a higher gain antenna (12dBi - 15dBI) may cause you to have a need to adjust the height of your antenna based on the access point location since the cone of transmission is significantly smaller than on medium gain antennas. Height is important to get clear of nearby obstacles however mounting the antenna on a mast of a sailboat is typically unnecessary. Since signal loss in the cable between the radio unit and the antenna increases rapidly with the length of the cable, it's better to locate the radio unit next to the antenna, and use lossless cable to support the radio unit, either USB or Ethernet, both of which have advantages and disadvantages (as noted below). Automatic Tracking There are products than can be used to keep a directional antenna aimed at an access point as a boat swings or drifts with precision of better than one degree (e.g., Track-It-TV). However, they are relatively expensive, and they only track in the horizontal plane, so it's important that the vertical beam width take into account rolling and pitching of the boat. Usually a vertical beam angle of 10 degrees or so is adequate for all but the roughest conditions, but even beam angles of 20 degrees or more can still result in substantial improvement in gain over an omnidirectional antenna. Temporary Setup Setup as needed, packed away when not in use. Ideally the radio unit and antenna are located together as high as possible (e.g., outside on the top of the cabin), usually connected by cable: USB thumb|Hawking HWU8DD Hi-Gain USB Wireless-G Dish Adapter Advantages: * Plug and play * Low cost (desktop type devices). * Power provided by USB cable, directly from the computer so no additional cabling is required. * USB Devices are designed for portable applications with quick (i.e. boat moving from port to port) setup. * Can often be used onshore as well as on the boat. * Using a software based access point (ICS), you have the ability to connect multiple computers or devices that use only built in Wi-Fi (such as iPhones and iPads) with no additional hardware purchase. Caveats: *Maximum length of a passive USB cable is 5 meters (about 16 feet), although that distance can be multiplied by means of one or more USB active extension cable(s), effectively a standard USB cable married to a one-port USB hub. (e.g., StarTech USB 2.0 Active Extension Cable USB2FAAEXT15). *Requires software drivers to be installed before the WiFi unit can be used. (Check with manufacturer to assure compatibilty with your particular operating system as not all units will work on all operating systems.) *Potentially more complex connection sharing. USB Internet connection can be shared by means of Internet Connection Sharing (on both Windows and Mac OS's). If using Microsoft Windows 7, this has become trivial via "Virtual WiFi". Connection Sharing will require the sharing computer to be left on whenever connection sharing is needed, however, no additional hardware or electricity requirments are needed in order to allow multiple devices to get online. *When running from a laptop battery, the power consumption (maximum USB port power is 500mA at 5v) of a high power Wi-Fi device will deplete the battery at a slightly higher rate than if using the computer with no external devices attached. (Actual rate will be dependent on the device being used, check manufacturer's specs.) Typical USB setup: *The Wirie - Long Distance, Easy to Use, Simple Installation, Affordable - Marine Grade, for Boats and RVs * Hawking HWU8DD Hi-Gain USB Wireless-G Dish Adapter (8 dBi, must be aimed) * 1 Watt USB WiFi Adpater with 7 db Gain Omni AntennaIncluded 15 feet of USB cable plus Optional 15 foot Active Extender Cable * Long Range Marine and RV WiFi System Ethernet Advantages: * Long cable (up to 300 feet or 100 meters) - masthead mounting becomes achievable. * No software driver needed, software built into ethernet based device. * Ability to create private network using switches, hubs and wireless routers (additional hardware and wiriing necessary). Ability to connect multiple computers or computers that use only built in Wi-Fi such as iPads, iPhones. Caveats: *Not all Wireless Ethernet client Bridges support multiple clients. Check manufacturer specs and/or Wi-Fi Wireless Ethernet Bridges. *Client bridges, repeaters, and routers all require a source of external power (110/220V or 12V). Devices require either a power cable or PoE (Power over Ethernet). Check manufacturer spec. *Depending on supplier, configuration and management can be more difficult for average computer users. Check supplier specs. Typical Ethernet setup: * Bitstorm BAD BOY Xtreme, Express, Unleashed Lots of general Wi-Fi information on their site. * Wi-Fi for Boats system uses the Ubiquity Bullet2HP Ethernet Router, 15 dBi Omni Antenna (pictured at right), Power Over Ethernet and Cat5e cable to conect the computer. * Ubiquiti Bullet Ubiquity Networks Nanostation2 and Bullet2 (or Bullet2HP). Includes a router so eliminates the problem of IP addressing both the client and the internet. Includes PoE from 12V. Range of many miles. * Buffalo Wireless-G High Power Ethernet Converter WLI-TX4-G54HP * Buffalo 6 dBi Detachable High Gain Directional Antenna WLE-AT-DACB (if needed, must be aimed) * http://www.caworldwifi.com/image.php?id=1&type=DWorld WiFi Client Setup * CA World WiFi Lightning/Surge Protection: This may protect your investment although lightning suppressors may cost as much as the Wi-Fi equipment itself. Permanent Installation Any permanent mount solution will give far more range than regular Wi-Fi at deck or cabin level: Ethernet: *Install marine-grade waterproof high-gain omnidirectional antenna. Non vented type suggested. Avoid the use of dish or directional antennas. *Install weatherized Ethernet device (e.g., ''Ubiquiti Bullet, SENAO SL-2611CB5 EXT or SOC-3220 or Bitstorm BAD BOY Xtreme) as close to antenna as possible in order to eliminate signal losses in antenna cable. *Run outdoor rated CAT5 cable from Ethernet device *Power device by running 12VDC or alternatively 110/220VAC using a Power Over Ethernet injector (power requirments vary by hardware). *At cabin end of Ethernet cable, attach: **Your computer **Hub or switch for wired network connections **Wi-Fi access point for private Wi-Fi rebroadcasting (e.g. Bitstorm BAD BOY Unleashed ) **Bluetooth access point (''e.g., ''ANYCOM AP-2002) (for Bluetooth network connections) '''USB': *Install marine quality USB device with non-vented omnidirectional antenna mounted next to the WiFi adapter. (e.g. The Wirie) *Run the USB cable into your boat from the WiFi system. *Extend the USB cable as needed to location inside your boat. Use Active USB extension cables to extend the length. *Install software for the WiFi adapter on the computer. *If desired, set up Internet Connection Sharing on a single computer to allow multiple computers/devices to access the USB WiFi device simultaneously. Managing a Wireless Ethernet Bridge frame|right|Wi-Fi at top of sailboat mast When using a wireless Ethernet client bridge, IP addresses of networked clients on the boat (wired or wireless) are normally assigned by a shore-based DHCP server. The problem is that the wireless Ethernet client bridge will typically have a fixed IP address for management that won't necessarily be on the same subnet as IP addresses set by shore-based DHCP servers, preventing networked clients from directly managing the wireless Ethernet client bridge. Possible solutions to this problem: # Use two network adapters {wired or wireless) on a given networked client: ## One configured by (shore-based) DHCP for Internet access ## The other configured manually just for managing the wireless Ethernet client bridge # Use a multi-homed Ethernet adapter with both a static address and a DHCP address # Use a client (ethernet adapter) that incorporates a router to create your own LAN (example Bitstorm BAD BOY Xtreme and Express). By adding a simple network switch, you can share the internet simultaneously with several computers. Wired versus Wireless Clients : Image:Boat Wi-Fi Wired vs Wireless.svg Note: In order to minimize possible interference, a boat Wi-Fi access point should ideally be on a different minimally-overlapping channel (1, 6, 11 in the USA) from the shore access point. Power Many standalone low-end networking devices that use separate "wall wart" type power supplies are able to tolerate a relatively wide range of input voltage, and can be run directly from 12 VDC boat power with an appropriate adapter cable. Check manufacturer input voltage specs if possible. LAN on a boat * When the boat has its own wireless access point (or wired hub or switch), and multiple network devices that get their IP addresses from a remote DHCP server, then all those IP addresses will be on the same subnet, and are thus part of a local area network (LAN). * It won't necessarily be a private LAN -- unless the remote wireless access point implements wireless-to-wireless isolation (which many do not), all boats will be on the same LAN, and should take precautions accordingly -- see Secure Internet access in a public hotspot. * That kind of LAN will be "up" (working) only when connected to remote Wi-Fi; otherwise it will be "down" (not working). * To have a private LAN, and one that works even when not connected to remote Wi-Fi, then use a local wireless router instead of a local wireless access point (or wired router instead of a wired hub or switch). That creates a "double NAT" which will usually work fine, although it can cause problems with certain older network protocols and applications. To access the LAN management port of the wireless Ethernet (client) bridge: ** Good method: If supported by your local wireless router, configure a manual route from LAN to WAN for a (RFC 1918) private IP address on the LAN management port. (The wireless router shouldn't forward private addresses without a manual route.) ** Crude method: Set a fake non-conflicting public IP address on the LAN management port of the wireless Ethernet (client) bridge, which your local wireless router will automatically forward to its WAN port (since it's not a local or private address). Relaying and Mesh Networks When some boats are too distant from a shore access point for a direct Wi-Fi connection, it may be possible to setup nearer boats to repeat or relay the Wi-Fi signal to more distant boats. See Wireless Distribution System. International Use Wi-Fi channels are standardized, but vary slightly in different parts of the world. Many Wi-Fi devices will work properly anywhere in the world, either by means of a configuration option (preferable), or by means of different firmware loads (clumsy). See Wi-Fi Channels. External Links *The Wirie - Long Distance, Easy to Use, Simple Installation, Affordable - Marine Grade, for Boats and RVs *Wi-Fi for Boats - Wi-Fi is a balance, you can not connect to what you can not receive. High Gain Omni Antennas. *Marine and Marina WiFi Equipment *[http://www.bitstorm.com Bitstorm BAD BOYAffordable High Power WiFi devices for marine, RV and trucking. Rock solid connections. 1 year warranty. **Bitstorm BAD BOY Xtreme | Express | Unleashed *Boatwifi.com brings you a long range, reliable wifi antenna *Long Range Marine and RV WiFi System *Wi-Fi Internet solutions for boaters and marinas *Complete Outdoor WiFi Solutions *RadioLabs **WaveRV Marine (complete USB system, but only 802.11b and WEP) *MarineNet Wireless **WiFi Antenna Installations *HyperLink Technologies **HyperGain HG2409UM 2.4 GHz 8.5 dBi Omnidirectional Wireless LAN Marine Antenna **12 Volt to 48 Volt DC/DC Boost Converter (for Power over Ethernet) *Linksys **WAP54GP Wireless-G Access Point with Power Over Ethernet (also works as Bridge) *Mini-Box.com **WRAP WIFI (modular components) *TRENDnet **Power over Ethernet (PoE) Injector TPE-101I *Track-It-TV Marine grade automatic tracking system for use with directional Wi-Fi antenna systems *The Wifi Shop (Good marine solutions and fast international service) *USB WIFI antenna and more *Marine set up Category:Wi-Fi